Apparatus for activating cement on shoe soles



Aug. 12, 1941. J. w. PRATT \ET AL APPARATUS FOR ACTIVATING CEMENT ON SHOE SOLES Filed Nov. 15, 1959 2 Sheets-Sheet 1 Au 12, 1941. J. w. PRATT ETAL 2,252,031

APPARATUS FOR ACTIVATING CEMENT ON SHOE SOLES Filed NOV. 15, 1939 2 Sheets-Sheet 2 I 1 WVf/VTUFS M Mm: g WfiW 2 Patented Aug. 12, "1941 UNITED STATES PATENT 2 OFFICE APPARATUS FOR ACTIVATING CEMENT ON SHOE SOLES Application November 15, 1939, Serial No. 304,564 In Great Britain December 7, 1938 11 Claims.

This invention relates to devices for activating thermoplastic cement and particularly for activating such cement after it has been applied to the soles of shoes. It has been the practice to attach soles to shoes by applying thermoplastic cement to the margin of the attaching face of an outsole, allowing it to form a dry film thereon and then, either with or without applying a similar coating of cement to the shoe, to heat the cement upon the sole and press the shoe and sole together. i

Objects of this invention are to provide a convenient and efiective apparatus for heat-activating cement on an outsole just prior to its being applied to a shoe and placed under pressure.

As illustrated herein, the apparatus comprises a support for the shoe sole and a heater so arranged that relative movement may be elfected between the support and the heater to bring the sole and the heater into such relative position that the coating on the sole will be subjected to the action of the heater, and means for automatically determining the length of time the sole will :be subjected to the action of the heater. In

the form of apparatus illustrated, a stationary electric heater is provided and the support for the sole is movable against spring tension from an inoperative position remote from the heater to a position in which the sole is presented in front of the heater, the support being held in this operative position by a latch. After the sole has remained exposed to the heater for a predetermined length of time the latch is automatically released, for example by the action of a dash-pot, and the carrier. is lifted by its spring away from its position in front of the heater. Masking means may be provided between the heater and the sole to protect uncemented portions of the sole from radiation, and a vessel containing water may be arranged adjacent to the heater to provide in the vicinity of the sole an atmosphere containing sufficient moisture to minimize drying out of the sole during its exposure to the heating means.

In the drawings,

Fig. 1 is a side elevation of apparatus embodying the present invention, the front being toward .the right;

-' heat from a heater 4%.

rights I2, I3. To each upright are pivoted two parallel links I4, I6, the links at their forward ends being pivoted to the four corners of a rectangular frame, designated generally by I8. The frame I8 (Fig. 2) is made up of two horizontal bars 20, 22 and two bars 24, 26 perpendicular to the horizontal bars. Secured to the upper and lower horizontal bars are a plurality of grid wires 28. The wires are bent rearwardly behind the lower horizontal bar 20 so that theyhave portions 30 (Fig. 1) adapted to support the lower edge of a sole placed on these portions. Two or more of the wires 28 extend farther upwardly, as at 34, to prevent a sole placed with its lower edge on the portions 30 from falling rearwardly. These wires, however, do not mask to any substantial extent the rear face of the sole from the action of the heater, which is to be later described.

The upper links I4 are provided with rearward extensions 35 which, rearwardly of the uprights I2, I3, are connected to the base It! by tension springs 36 which normally serve to hold the frame It in an upper position, as indicated in dash lines in Fig. 1, the frame while in this position being loaded with a sole S (indicated in dash lines in Figs. 1 and 2) the cement on which is to be heated. When so loaded, the frame I8 is moved downwardly by the operator into the position shown in full lines in Figs. 1 and 2, the frame I8 having a handle 38 which the operator may grasp when the frame is to be lowered. In the lowered position of the frame, the sole S supported thereby has the coating on its attaching face, which will be to the left in Fig. 1, subjected to radiant The heater comprises a plate of about the same over-all length and width as the sole, this plate having closely spaced, spirally wound, electric heating elements 42 arranged. along the length of the plate so that the heat radiation will be substantially uniform throughout the length of the heater. Current is supplied to the heater through leads 44 and the heater is secured by brackets 46 to the base If]. The heater 4B is preferably inclined forwardly at a small angle to the vertical and the links I4, I6

are so arranged that when the frame is in operative position (Fig. 1) it will be parallel to the heater 40.

Supported on the base III is a container 48 which may be rectangular in cross-section and of a length somewhat greater than that of the frame I8. The rear wall of the container is lower than the front wall to provide clearance for the frame I8 in its lower position. In the container a supply of water is maintained at about the level indicated in Fig. 1. When the frame is in its normally raised position, direct heat from the heater 40 reaches the water in the container, the arrangement being such that the water is maintained at a temperature somewhat above room temperature, for example about 110 F. A sheet 58 of asbestos masks the forward side Wall of the container from the heater and prevents this side wall from becoming unduly hot and radiating appreciable heat to the uncoated surface of a sole being treated. The vapor rising from the slightly heated water in the container insures that the atmosphere around the sole while it is being heated will contain sufficient moisture to prevent substantial drying out of the sole while the cement is being activated, the sole being at this time in mellow temper preparatory to its attachment to a shoe.

Since it is usual to apply cement only to the marginal portion of the attaching face of the sole, there will be a central portion of that face, at least at the forepart of the sole, which will be uncoated. In order to prevent direct radiation of heat from the heater ii! to the uncoated central portion of the sole, a masking plate 52 is supported at the proper location in front of the heaterby wires 54 extending downwardly from a sheet 56 of asbestos or similar material which iscarried by brackets 58 fixed to the uprights l2, 13. The masking plate 52, as seen in Fig. 2, is of a shape corresponding to the uncemen-ted area of the forepart of the sole and is located to intercept direct radiation from the heater 4%] to the uncoated central portion of the forepart of the sole. The sheet 56 serves to'avoid or reduce radiation of heat from the heater 40 toward the frame 18 when the latter is in its raised position.

Assuming that the frame l8 with a sole thereon has been lowered against the tension of the springs 35 to a position in front of the heater 40, as illustrated in Fig. 1, the illustrated means for holding the frame in that position and for releasing it after a predetermined period of time will now be described. At the rear of the apparatus is a mechanical dash-pot 66 into which a rack-bar 62 extends, the rack-bar being pivoted at 63 to a bracket 64 secured to the base to. The dash-pot 60 has an extension 66 to which is fixed a rod 68 and a crossbar l0. Threaded rods 12 extend through slots in the ends of the crossbar E and are connected at their lower ends by springs M to the base at 75, the arrangement being such that if the dash-pot 60 is moved with respect to the rack-bar 62 in a direction away from the bracket 64 the springs I i will be stretched and the dash-pot will tend to return under the action of the springs but at a slow rate, owing to the resistance to rotation of certain parts provided within the dash-pot which are geared to the rack-bar 62. The threaded rods 1 12 are provided with wing nuts 16 by the turning of which the tension of the springs i l may be adjusted to vary the rate at which the dash-pot 60 will be drawndown by them.

Connecting the rear ends of the extensions 35 of the links [4 is a crossbar 18 on the middle portion of which is a tooth 80 which projects upwardly and rearwardlya-nd on which also is an arm 82 which projects downwardly and'rearwardly. When the frame I8 is in its raised position the dashpot is supported against forward swinging movementabout the pivot 63'bya support 84 upstanding from the base Hi. When the frame is is depressed'lnto the positionshown in full lines in Fig. 1, the turning movement of the extensions 35 causes the crossbar I8 to move toward the rod 68 until the tooth 80 engages the rod, this occurring before the rod is engaged by the arm 82. The tooth 80 moves up the surface of the rod 68 until it engages a ledge 86 formed by the upper end of a recess in the front surface of the rod. When the tooth 80 has engaged the ledge 86, continued movement of the extensions 35, as the frame I8 is pressed downwardly, causes the tooth 80 to pull the rod 68 upwardly, causing the dashpot to move upwardly with respect to the rack-bar 62, thereby stretching the springs '14. When the frame I3 is approaching its lowermost position, the arm 82 engages the rod 68 and serves to push the rod slightly forwardly, thereby releasing the ledge 86 from the tooth 80. The cross-bar 18 carries a rearwardly projecting pin 88 which, just before the frame I8 reaches its lowermost position, engages an inclined surface'iifl (Fig. 3) formed on a latch 92 which is freely pivoted on a screw 94 to the inclined upper end portion of a fixed bar 96 the lower end of which is secured to the base If]. The pin 83 acts on the inclined surface 90 to swing the latch 82 until the pin passes above a step 98 on the latch, whereupon the latch moves back by gravity to its initial position. This will take place just as the frame I8 has reached its lowest position which is determined by engagement of the crossbar 18 with a bracket )0 secured to the fixed bar 95. The sole will now be in a position in front of the heater 4!) and the operator will release downward pressure on the handle 38. Engagement .of the pin 88 with the latch 92 will now prevent the frame l8 and the sole carried thereby from moving upwardly in response to the action of the springs 36. The rod 68, having now been released as described from the tooth 89, will be moving slowly downward under the action of the springs 14, the arm 82 now holding the rod 68 in such position that the ledge 86 is clear of the tooth as the rod moves downwardly. Near its upper end the rod 68 has a collar I92 adjustably secured thereon by a set screw I04. When the rod 68 has moved downwardly through a distance and for a time determined by the position at which the collar I02 i located on the rod 68, the collar 16?. engages an arm I06 (Fig. 3) which extends sidewise from the latch 92 and turns the latch to cause the step 98 to move from under the pin 88. When this happens the frame I8 is moved upwardly by the springs 36, carrying the frame and the activated sole thereon away from the heater 40.

It will be understood that the sole will have remainedin front of the heater for a predetermined period of time equal to that required for the dash-pot to travel from its fully raised position to the position it occupies when the collar I02 turns the latch 92 to release the pin 82. This predetermined period of time during which the cement on the sole is subjected to heat activation may be varied by turning thenuts '16 to vary the tension of the spring 14 and/or adjusting the position of the collar 12 on the rod 68. The length of the activation period will be so adjusted that the cement coating on the sole will be brought to just the desired heat-activated condition and no longer than is required to effect this condition. With the proper adjustments the sole does not have to be left long enough in front of the heater to cause the bodily temperature of the sole to be raised to any substantial degree.

Having thus described our invention, what we claim as new and desire to secure by Letters Patent of the United States is:

1. Apparatus for subjecting thermoplastic cement on tempered shoe soles to heat activation comprising a heater, a support for the sole, the initial relative positions of the heater and sole support being such that the sole is not heated, means for relatively moving the heater and the support to dispose the sole in heating relation to the heater, means acting after a predetermined time to restore the initial relative positions of the heater and sole support, and means for maintaining the moisture in the sole While it is being heated.

2. Apparatus for subjecting thermoplastic cement on shoe soles to heat activation comprising a heater, a support for the sole, the initial relative positions of the heater and sole support being such that the sole is not heated and the heater and the support being relatively movable to dispose the sole in heating relation to the heater, means acting at a predetermined time after relative movement of the heater and sole support into heating position to restore the initial relative positions of the heater and sole support, and a plate in front of the heater to protect from radiation the part of the sole which is not coated with cement.

3. Apparatus for subjecting thermoplastic cement on shoe soles to heat activation comprising an electric heater the elements of which are in a plane, said heater being disposed to radiate heat downwardly and forwardly, a sole carrier mounted for downward swinging movement from a remote position above the heater to a position in front of the heater and in parallelism therewith, springs tending to swing the carrier upward and away from the heater to said remote position, a latch to hold the carrier in position in front of said heater, and means set by the downward swinging movement of said carrier to release the latch after a predetermined time has elapsed.

4. Apparatus for subjecting thermoplastic cement on shoe soles to heat activation comprising a heater, a sole-carrying frame, uprights, parallel links pivoted to the uprights at one end and to the frame at the other, the upper links being extended rearwardly beyond their pivots, a crossbar connecting the rearward extensions, an extensible dash-pot pivoted at its lower end and at its upper end carrying a rod, a ledge thereon, springs tending to contract the dash-pot, means on the crossbar to engage said ledge and extend said dash-pot when the frame is depressed, a latch to hold the frame in depressed position, and means operated by contraction of the dash-pot in response to said springs to release the frame.

5. Apparatus for subjecting thermoplastic cement on shoe soles to heat activation comprising a heater, a sole-carrying frame movable into and out of heating position in front of the heater, a dash-pot, spring means for holding the dash-pot in contracted condition, a member extending from said dash-pot having an abutment surface, means operated by movement of the frame into position in front of the heater for engaging said abutment surface to extend the dash-pot, means for disengaging said last-named means from said abutment surface when said frame reaches heating position to permit contraction of the dashpot, a latch for locking the frame in said heating position, means operated at a predetermined point in the contraction of the dash-pot to trip said latch and release the frame, and spring means for moving the frame out of heating relation to the heater after it has been released.

6. Apparatus for subjecting thermoplastic cement on shoe soles to heat activation comprising a heater arranged to radiate heat downwardly and forwardly, a water tank in front of the heater having a high front wall to deflect heat rearwardly, means for supporting a sole in front of the heater between the heater and said wall, a latch for holding the sole support in place, means tending to move the support out of position in front of the heater, and means for releasing the latch at a predetermined time after the sole-supporting means has been moved in front of the heater.

7. Apparatus for subjecting thermoplastic cement on shoe soles to heat activation comprising a heater, a support for the sole, the initial relative positions of the heater and sole support being such that the sole is not heated, means for relatively moving the heater and the support to dispose the sole in heating relation to the heater, means acting after a predetermined time to restore the initial relative positions of the heater and sole support, and means for creating about the heater an atmosphere of high moisture content in which the sole is immersed during the action of the heater thereon to minimize drying of a tempered sole while the cement thereon is subjected to heat activation.

8. Apparatus for subjecting thermoplastic cement on shoe soles to heat activation comprising an electric heater arranged to radiate heat downwardly and forwardly, a Water tank in front of the heater having a high front wall to deflect heat rearwardly, means for supporting a sole in front of the heater between the heater and said wall, a latch for holding the sole support in heating position, means tending to move the support out of position in front of the heater, and means comprising a contractible dash-pot arranged to be extended by movement of the sole support to a position in front of the heater, said dash-pot acting at a predetermined time in its contraction to release said latch.

9. Apparatus for subjecting thermoplastic cement on shoe soles to heat activation comprising a heater, a sole-carrying frame, uprights, parallel links pivoted to the uprights at one end and to the frame at the other, the upper links being extended rearwardly beyond their pivots, a crossbar connecting the rearward extensions, an extensible dash-pot tending slowly to contract after extension, said dash-pot carrying a rod having a ledge thereon, a tooth on the cross-bar to engage said ledge and extend said dash-pot when the frame is depressed, means for releasing said ledge from said tooth to permit contraction of the dash-pot, a latch to hold the frame in heating relation to the heater, means operated by contraction of the dash-pot to release the latch, and means for lifting the frame when so released.

10. Apparatus for subjecting thermoplastic cement on shoe soles to heat activation comprising a heater, a sole-carrying frame, uprights, parallel links pivoted to the uprights at one end-and to the frame at the other end, the upper links being extended rearwardly beyond their pivots, a crossbar connecting the rearward extensions of said upper links, spring means tending to swing the links to move said frame away from the heater, a handle for moving said frame into heating position in front of said heater, means for holding the frame in the heating position against the action of said spring means, and means for releasing said frame from said holding means at a predetermined time after it has been moved into heating position.

11. Apparatus for subjecting thermoplastic cement on shoe soles to heat activation comprising a heater disposed to radiate heat downwardly and forwardly, a sole carrier mounted for downward swinging movement from a remote position above the heater to a position in front of the heater and in parallelism therewith, springs tending to swing 10 the carrier upward and away from the heater to said remote position, a latch to hold the carrier in position in front of said heater, means to release the latch after a predetermined time has elapsed, and means for shielding said carrier from said heater when the carrier is in said remote position above the heater.

JOHN WILLIAM PRATT. HUBERT BOOTHROYD. 

